The present invention relates to a method and a system for ascertaining the consumption habits of a test population, and, more particularly the television consumption habits of a test population. Data regarding the habits, in particular, determination of the television channel, either by determining the program switched on and/or interrogation of the population, is automatically memorized in locally arranged apparatuses and the memorized data is preferably transmitted by telephone to a central computer for evaluation. Systems as described above are on the market from different sources and they are used in different countries, in particular for investigating the television consumption habits.
A first decisive object of such methods and systems relates to the reliable automatic determination of the television channel, respectively the program switched on. Published German application DE-OS 33 42 949 relates to a method of determining of the channel selection in a television receiver (TV-receiver). This known method presupposes that to each TV-receiver there is associated a locally arranged apparatus which has to determine from the tuning voltage which channel is witched on, respectively which channel is received. This known procedure presupposes an individual adaption of each single locally arranged TV-receiver and this not only at the time of the first installation of the apparatus but generally also at each modification of the transmitted frequencies and starting of new transmitters.